UNI101Y1 Study Guide - Genetic Drift, Daniel H. Janzen, Species Richness
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Bio120h lisa zhao 2011 | page 6. Even though tree species might be specialized for diff. kinds of germination sites, which species actually invade a gap depends more on the vagaries of recruitment than on envmtal conditions of the gap. Competitive exclusion decreases and diversity increases (self-accelerates diversity) Species in more diverse forests exhibit less variation in growth ad survival rates higher species richness is associated with more similar life histories. Herbivory is responsible for species richness in tropics. Herbivores feed on buds, seeds, and seedlings of abundant species efficiently enough to reduce their densities allows less common species to grow in their place. Abundance makes a species vulnerable to consumers pest pressure hypothesis. Exert strong selection pressure on potential consumers to specialize on them. Ex. attempts to establish plants in monoculture fail. Pp hypothesis predicts that seedlings should be less likely to become established close to adults of the same species (self-limitation)